The c-fgr proto-oncogene was shown to be expressed in human B-cells infected with EBV. This is the first demonstration of the induction of human proto-oncogene expression by a DNA virus. The dbl oncogene isolated by A. Eva was characterized in more detail. Probes for comparing the transforming gene to its normal counterpart were prepared and also used to isolate dbl cDNA and study dbl expression in normal and malignant tissues. In research on animal lentiviruses the regulatory regions (LTR) of the caprine arthritis encephalitis virus were sequenced. The genome of the equine infectious anemia virus (EIAV) was molecularly cloned and its nucleotide sequence determined. Broadly reactive radioimmunoassays for detection of animal lentiviruses were developed. Protein products of the EIAV genome are being expressed in bacteria.